I played for about an hour and so far I'm not feeling it.
I beat the first boss I encountered and found the fight satisfying but I'm beginning to get the feeling that trading tight level design for an open world was not a good idea.
I hope I'm unlucky and just haven't found any well-designed levels that can be accessed from the overworld or something like that and the good stuff's just around the corner, but so far, not a good first impression.